Evaluating the Efficacy of US Virgin Islands Marine Protected Areas: Look Before You Leap!

Marine protected areas (MPA) are an important tool for management of marine ecosystems.  In 2001, the Virgin Islands Coral Reef National Monument (VICR) in St John, US Virgin Islands was established by Presidential Executive Order under the Antiquities Act. The primary objectives of this study were to characterize and monitor coral habitat and reef fish assemblages to assess the efficacy of the MPA.  The VICR is comprised of five areas and this investigation addressed the mid-shelf reef (MSR) area that ranges from approximately 2-7 km offshore south from St. John and within Coral Bay (CB), a southeast shore embayment.  The VICR prohibits almost all extractive uses. Surveys of habitat and fishes inside and outside of the VICR- MSR and VIC-CB were conducted in 2003–2010.  Areas outside the VICR-MSR had significantly more scleractinian corals, greater habitat complexity, and greater species richness and abundance of reef fishes than areas within the VICR. No significant difference in reef fish richness or biomass was detected between inside and outside the VICR-CB, but the density of fishes was significantly greater outside VICR-CB.  For both components of the VICR over the study period, a decreasing trend was observed in scleractinian corals for both inside and outside sites, while an increasing trend in macro-algal cover was observed both within and outside VICR.  Due the administrative process used to delineate the boundaries of the VICR and possibly the ecological impacts of the coral bleaching event, the enhancement of the marine ecosystem within and outside the VICR may not be fully realized or increases in economically important reef fishes may take longer to detect.